CDL Air brakes Flashcards
(34 cards)
The Spring brakes used on the chambers in a straight truck will bring you to a stop when air pressure drops below psi
- 20
- 100
- 60
20
The safety Valve is set automatically when pressure is
1.150
2. 100
3. 50
150
If your truck or bus has dual parking control valves, you can use pressure from a separate tank to:
1.Release the spring emergency/parking brakes to move a short distance
2. stay parked twice as long without using up service air pressure
3.balance the service brake system when you are parked
Release the spring emergency/parking brakes to move a short distance.
If your truck has a properly functioning dual air brake system and minimum size air tanks, the air pressure should build up to 85 to 100 psi within how many seconds
- 30
- 60
- 45
45
During normal driving, spring brakes are usually held back by
- spring pressure
- air pressure
- bolts or clamps
air pressure
The air compressor stops pumping air at what psi
- 125
2.150
3.100
125
The driver must be able to see how low air pressure warning witch comes on before pressure in the service air tanks fall below psi
- 80
- 40
- 60
60
If your vehicle has an alcohol evaporator, every day during cold weather you should:
- check the oil for alcohol content
- check and fill the alcohol level
- change the alcohol from a bottle
check and fill the alcohol level
The air loss rate for a straight truck or bus with the engine off and the brakes on should not be more then :
- 3 psi in one min
- 2 psi in 45 seconds
- 1 psi in 30 seconds
3 psi in one min
The air brake lag distance at 55 mph on dry pavement adds about feet
- 12
- 32
- 52
32
Repeatedly partially increasing and pressing the brake pedal may result in
- no change of brake air pressure
- a loss of brake air pressure
- a buildup of brake air pressure
a loss of brake air pressure
An air brake system is fully charged at what pai
- 125
- 100
125
The spring brakes used on the chambers in a straight truck will bring you to a stop when air pressure drops below psi
- 20
- 60
20
If your truck has a properly functioning dual air brake system and minimum-sized air tanks, the air pressure should build up from 86 to 100 psi within how many seconds
- 45
- 60
45
If you are driving down a steep downgrade and have reached your safe speed of 40 mp, you would apply the service brake until your speed dropped to mph?
- 35
- 25
35
In ideal conditions a truck or bus with air brakes going at 55 mph would require the stopping distance of how many feet?
- From 100 to 300 feet
- More than 300 feet
300 feet
The proper use of the brakes when going down a long steep grade after selecting a properly gear is to brake until your speed is about _ below the posted speed and release your brake.
1.10
2. 5
5
Parking or emergency brakes of trucks and busses can be legally held on by _ pressure
- Spring
- Air
Spring
A slack adjusters free play needs to be adjusted if it is more than about _ when you pull hard on it
- 1 inch
- 1/2 inch
1 inch
The parking or emergency brakes on a heavey vehicle can only be held in position by something thay cannot leak away like
- Hydraulic pressure
- Spring pressure
Spring pressure
It is not sage to drive a vehicle that has brake drums with cracks that are longer than _ of the width of the friction area
- 1/2
- 1/4
1/2
Stab braking
1. Apply your brakes all the way. Release the brakes when wheels lock up. As soon as the wheels start rolling, apply the brakes fully again
2. Use light steady pressure on the brake pedal
Apply your brakes all the way. Release the brakes when wheels lock up. As soon as the wheels start rolling, apply the brakes fully again
The brake system thay applies and releases the brakes when the driver uses the brake pedal is the _ brakes system.
- Service
- Emergency
- Hydulic
Service
Repeatedly partially increase and pressing the brake pedal mau result in
- A buildup of brake air pressure
- A loss of brake air pressure
A loss of brake air pressure
